When compared with moms who had difficult deliveries ending in vaginal birth, women in the study who had cesarean deliveries said they had more problems getting pregnant after the birth of their first child.
Whale is the common name for a widely distributed and diverse group of fully aquatic marine mammals. They are an informal grouping within the infraorder Cetacea, excluding dolphins and porpoises, so to zoologists the grouping is paraphyletic.dontocetes feed largely on fish and squid. A few, like the sperm whale, feed on large invertebrates, such as giant squid. Grey whales are specialized for feeding on bottom-dwelling molluscs. Male whales typically mate with multiple females every year, but females only mate every two to three years.
Killer whales rule the sea thanks to their impressive physical characteristics. They can grow to be nearly as long as a school bus and weigh up to 12,000 pounds. They also possess a mouth full of sharp teeth that can grow to be four inches long. Killer whales are very social animals that live in groups called pods. Pods can have as many as 40 members that stick together to hunt for food. Like the dolphins they're related to, killer whales use echolocation to communicate with each other.